Aiz,
Where in Oz are you?
There are many jobs from Commercial Art to being the next Ken Done or Pro Hart (he he), you can work as a set decorator in the theatre too, just look around and see where there is anything that is painted or drawn and there is sure to be someone behind it with a pencil or brush. Oh and don't forget book illustrator.
You can go to Uni & do a Fine Arts Degree and see what comes out of that, too.
Personally I would love to earn a living from my art, but I need to work to keep the money coming in until I am recognized as the next great talent

(as if).
You could always do what I do - I fell into doing animal portraiture (see my gallery) and so I accept the odd commission with the hopes that at some stage I will become good and fast enough (I am incredibly slow at times) to change my working hours to favour me doing more art. Or at least to have it pay for ALL my art indulgences (not just materials but the books and references that I get too).
Whatever way you go - enjoy the ride. Life is too short for regrets, I know at your age it doesn't seem so, but just chalk up anything that isn't just what you had planned, to experience.
If you can do that and look at everything (a MacDonalds job if it comes to that) as fodder for your art (even the Masters painted what they saw in everyday life), then you can get the most out of anything that comes your way, and improve your talent as you go.
Hope that helps